This is a study of cardiovascular disease in groups expected to have highly contrasting rates on the basis of the low frequency found in white women, approximating half that of men, and the virtual obliteration of this advantage in women with diabetes mellitus. The subjects, initially chosen from prenatal clinics, were negative controls (328), i.e. every Nth patient with a normal three-hour glucose tolerance test (GTT), and prediabetics (685), i.e. all those with an abnormal GTT which returned to normal postpartum. Annual testing followed in a longitudinal study for sixteen years with examinations to document cardiovascular disease. One-third of the prediabetics now have diabetes mellitus and the remainder reveal all grades of evolving diabetes. The unusual opportunity of investigating etiologic clues for cardiovascular disease provided by these contrasting groups of white women that cover the whole spectrum of emerging carbohydrate intolerance will be enhanced by parallel information on racial differences from the thirty percent black component of the population. Study end-points will include blood pressures, graded exercise electrocardiograms, peripheral vascular disease by segmental blood pressures using Doppler ultrasonic velocity detectors following exercise, peripheral pulse wave contours, and a standardized history for angina pectoris, TIAs, intermittent claudication, and myocardial infarction. Examiation will document congestive heart failure, renal, cerebral and fundoscopic abnormalities. Blood studies will include GTTs, cholesterol and triglycerides with detailed quality control procedures. Lipoprotein phenotyping and identification of secondary hyperlipoproteinemics will be included.